Mortimer Clarke county court claim

[Coconutmilk]

I have received a county court claim from Mortimer Clarke acting on behalf of Cabot Financial for Next Retail. Inhave been away from home caring for family and the date of issue was 14/02/20 which means the date of service as 19/02/2020. I acknowledged receipt yesterday when I retrieved the paperwork at home - which was on the 14th day from date of service so was in time. I have ticked to defend in full and am just completing the letters for subject access request etc. Just confused as to when I need to file defence? Is it 28 days from date of service meaning 18/03/2020? As I need to make reference on it for the CPR 31.14 request to Mortimer Clarke. Many thanks